Incandescent headlight lamp having critically positioned filaments



g- 10, 1955 R MICKLEY 3,200,282

FIG.|

INVENTOR.

Rolf Mickley ATTORNEY$-.

United States Patent 3,200,282 INCANEESQIENT HEADLIGHT LAME HAVENG @RHTECALLY POSITIONED FILAMENTS Rolf Micldey, 8 Elisahethstrasse, Munich, Germany Fitted .luly 5, 1962, Ser. No. 207,678 Claims priority, application Germany, July 21, 1961, M 51,264 3 (Ilaims. (Cl. 313 114) In conventional parabolic main headlights for motor vehicles, which on the one hand usually emit a high beam that is strongly diffused and dazzling in all directions and on the other hand emit a down-beam, the high beam has meanwhile become almost useless for practical purposes due to the steadily increasing density of trafiic on roads used by night so that the high beam can scarcely be utilized. Whereas formerly the high beam was the chief type of lighting and the down beam was merely a sort of temporary auxiliary light, the position at present is the opposite. Almost continuous driving with the short-range down beam, however, forces drivers to maintain only low speeds owing to the restricted visibility, and this, in turn, does not contribute towards the maintenance of a smooth flow of traffic, and certainly does not improve road safety.

The object of the invention is to provide a remedy by directing the rays of the high beam in such manner that the very dazzling glare caused by light from the headlights, which among other things normally produces intensive radiation directed upwards above the level of the headlights and in fact produces the greatest luminous intensity in this area, is reduced to such a degree that essen tially there remains only a concentrated horizontal beam of radiation from the entire headlight and at the same time a downward diffusion of such beam. By this means not only the illumination level required for high speeds is preserved in the form of a far-reaching beam in the horizontal plane through the centre of the headlight, but also the illumination of the road is ubstantially improved in respect of both the carriageway surface and the edges of the road.

In view of the fact that up to the present it is not technically feasible to make or use a sufficiently small punctiform light source for conventional parabolic headlights for automobiles, the invention aims at producing an approximation of the effect of such a light source by creating an approximately similar non-dazzling high beam, utilizing the entire parabolic reflector, by means of a high beam filament passing through or round the focal point and of double screening means precisely located relative to such filament in certain reference planes governed by the geometry of the headlight.

FIG. 1 is a side, cross-sectional view taken through the axis of the parabolic reflector.

FIGS. 2, I, and II, are views from above and below, respectively, of the pair of filaments and shields of FIG. 1.

FIGS. 2, III and IV, are views similar'to FIGS. 2, I and If, showing a modified form of the pair of filaments.

The invention is characterized by the fact that, in accordance with the attached drawing-FIG. 1the highbeam filament 3 which may be a helically coiled filament, extends along the headlight axis 5 and passes through the focal point 2, the filament windings lying in front of the focal point being shielded on the under side by shielding means 1 and the rear filament windings lying behind the focal point being shielded on the upper side 2 by shielding means In while the focal point is left exposed in both 3-,2,Z82 Patented Aug. 10, 1965 ice cases, the said shielding being accomplished in such manner that the dimensions of the two shielding means are fixed at both outer limits by the integral high-beam filament lying horizontally along the headlight axis and passing through the focal point on the one hand and at both inner limits by the plane 6 normal to the headlight axis and passing through the focal point of the headlight paraboloid 7 on the other hand, the down-beam filament 8 being a coiled-coil filament separated into two connected coils mounted symmetrically with respect to both sides of the high beam filament in the rear space that is shielded on the upper side. Thus, shielding means 1 and la may be of semicylindrical form concentric with respect to filament 3. In FIG. 2, drawing I is a view of the filament from above, and drawing II a view from below. Drawings III and IV show the same double shielding system in conjunction with an arc-shaped main filament 3a. Drawing III is a view from above and drawing IV a view from below of the double shielding system, in which the areshaped high beam filament is marked 3a and in which the down-beam filament 8a lies under the shield between the two arms of the arc-shaped filament 3a. The numerals in the other parts of the drawings correspond to those in FIG. 1.

I claim:

1. In a two filament headlight lamp of the type having a high beam filament and a low or down beam filament and a parabolic reflector,

a high beam filament extending substantially along the axis of said parabolic reflector through the focal point with portions thereof extending in front of the focal point and portions extending to the rear of the focal point,

a first shielding means extending over that portion of the high beam filament which extends to the rear of the focal point,

a second shielding means extending below that portion of the high beam filament which extends in front of the focal point,

the outer end of the first shielding means and the inner end of the second shielding means being slightly spaced axially with respect to the axis of said parabolic reflector whereby light beams from the high beam filament projecting at right angles to the focal point of said reflector pass directly to said parabolic reflector,

said low beam filament being positioned substantially entirely below the first shielding means.

2. The two filament headlight lamp of claim 1 wherein the low beam filament is a coiled filament of two connected coils symmetrically disposed on opposite sides of the high beam filament.

3. The two filament headlight lamp of claim 1 wherein said high beam filament is a coiled filament of arcuate configuration, said low beam filament being positioned between the two arms of the high beam filament.

References Cited by the Examiner UNITED STATES PATENTS 1,451,161 4/23 Helm 313- X 2,277,685 3/42 Bergstrom 313-l14 X 3,148,301 9/64 Johnson 313-113 X GEORGE N. WESTBY, Primary Examiner. DAVID J. GALVIN, Examiner. 

1. IN A TWO FILAMENT HEADLIGHT LAMP OF THE TYPE HAVING A HIGH BEAM FILAMENT AND A LOW OR DOWN BEAM FILAMENT AND A PARABOLIC REFLECTOR, A HIGH BEAM FILAMENT EXTENDING SUBSTANTIALLY ALONG THE AXIS OF SAID PARABOLIC REFLECTOR THROUGH THE FOCAL POINT WITH PORTIONS THEREOF EXTENDING IN FRONT OF THE FOCAL POINT AND PORTIONS EXTENDING TO THE REAR OF THE FOCAL POINT, A FIRST SHIELDING MEANS EXTENDING OVER THAT PORTION OF THE HIGH BEAM FILAMENT WHICH EXTENDS TO THE REAR OF THE FOCAL POINT, A SECOND SHIELDING MEANS EXTENDING BELOW THAT PORTION OF THE HIGH BEAM FILAMENT WHICH EXTENDS IN FRONT OF THE FOCAL POINT, THE OUTER END OF THE FIRST SHIELDING MEANS AND THE INNER END OF THE SECOND SHIELDING MEANS BEING SLIGHTLY SPACED AXIALLY WITH RESPECT TO THE AXIS OF SAID PARABOLIC REFLECTOR WHEREBY LIGHT BEAMS FROM THE HIGH BEAM FILAMENT PROJECTING AT RIGHT ANGLES TO THE FOCAL POINT OF SAID REFLECTOR PASS DIRECTLY TO SAID PARABOLIC REFLECTOR, SAID LOW BEAM FILAMENT BEING POSITIONED SUBSTANTIALLY ENTIRELY BELOW THE FIRST SHIELDING MEANS. 